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From: Christoph Lameter <clameter@sgi.com>
To: Robin Holt <holt@sgi.com>
Cc: Andrea Arcangeli <andrea@qumranet.com>,
	Nick Piggin <npiggin@suse.de>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>,
	linux-mm@kvack.org,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	steiner@sgi.com, linux-kernel@vger.kernel.org,
	Avi Kivity <avi@qumranet.com>,
	kvm-devel@lists.sourceforge.net, daniel.blueman@quadrics.com,
	Hugh Dickins <hugh@veritas.com>
Subject: Re: [kvm-devel] mmu_notifier: invalidate_range_start with lock=1
Date: Wed, 30 Jan 2008 18:56:38 -0800 (PST)	[thread overview]
Message-ID: <Pine.LNX.4.64.0801301851310.14263@schroedinger.engr.sgi.com> (raw)
In-Reply-To: <20080131023401.GY26420@sgi.com>

One possible way that XPmem could deal with a call of 
invalidate_range_start with the lock flag set:

Scan through the rmaps you have for ptes. If you find one then elevate the 
refcount of the corresponding page and mark in the maps that you have done 
so. Also make them readonly. The increased refcount will prevent the 
freeing of the page. The page will be unmapped from the process and XPmem 
will retain the only reference.

Then some shepherding process that you have anyways with XPmem can 
sometime later zap the remote ptes and free the pages. Would leave stale 
data visible on the remote side for awhile. Would that be okay?

This would only be used for truncate that uses the unmap_mapping_range 
call. So we are not in reclaim or other distress.




  parent reply	other threads:[~2008-01-31  2:56 UTC|newest]

Thread overview: 70+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-01-28 20:28 [patch 0/6] [RFC] MMU Notifiers V2 Christoph Lameter
2008-01-28 20:28 ` [patch 1/6] mmu_notifier: Core code Christoph Lameter
2008-01-28 22:06   ` Christoph Lameter
2008-01-29  0:05   ` Robin Holt
2008-01-29  1:19     ` Christoph Lameter
2008-01-29 13:59   ` Andrea Arcangeli
2008-01-29 14:34     ` Andrea Arcangeli
2008-01-29 19:49     ` Christoph Lameter
2008-01-29 20:41       ` Avi Kivity
2008-01-29 16:07   ` Robin Holt
2008-02-05 18:05   ` Andy Whitcroft
2008-02-05 18:17     ` Peter Zijlstra
2008-02-05 18:19     ` Christoph Lameter
2008-01-28 20:28 ` [patch 2/6] mmu_notifier: Callbacks to invalidate address ranges Christoph Lameter
2008-01-29 16:20   ` Andrea Arcangeli
2008-01-29 18:28     ` Andrea Arcangeli
2008-01-29 20:30       ` Christoph Lameter
2008-01-29 21:36         ` Andrea Arcangeli
2008-01-29 21:53           ` Christoph Lameter
2008-01-29 22:35             ` Andrea Arcangeli
2008-01-29 22:55               ` Christoph Lameter
2008-01-29 23:43                 ` Andrea Arcangeli
2008-01-30  0:34                   ` Christoph Lameter
2008-01-29 19:55     ` Christoph Lameter
2008-01-29 21:17       ` Andrea Arcangeli
2008-01-29 21:35         ` Christoph Lameter
2008-01-29 22:02           ` Andrea Arcangeli
2008-01-29 22:39             ` Christoph Lameter
2008-01-30  0:00               ` Andrea Arcangeli
2008-01-30  0:05                 ` Andrea Arcangeli
2008-01-30  0:22                   ` Christoph Lameter
2008-01-30  0:59                     ` Andrea Arcangeli
2008-01-30  8:26                       ` Peter Zijlstra
2008-01-30  0:20                 ` Christoph Lameter
2008-01-30  0:28                   ` Jack Steiner
2008-01-30  0:35                     ` Christoph Lameter
2008-01-30 13:37                     ` Andrea Arcangeli
2008-01-30 14:43                       ` Jack Steiner
2008-01-30 19:41                         ` Christoph Lameter
2008-01-30 20:29                           ` Jack Steiner
2008-01-30 20:55                             ` Christoph Lameter
2008-01-30 16:11                 ` Robin Holt
2008-01-30 17:04                   ` Andrea Arcangeli
2008-01-30 17:30                     ` Robin Holt
2008-01-30 18:25                       ` Andrea Arcangeli
2008-01-30 19:50                         ` Christoph Lameter
2008-01-30 22:18                           ` Robin Holt
2008-01-30 23:52                           ` Andrea Arcangeli
2008-01-31  0:01                             ` Christoph Lameter
2008-01-31  0:34                               ` [kvm-devel] " Andrea Arcangeli
2008-01-31  1:46                                 ` Christoph Lameter
2008-01-31  2:34                                   ` Robin Holt
2008-01-31  2:37                                     ` Christoph Lameter
2008-01-31  2:56                                     ` Christoph Lameter [this message]
2008-01-31 10:52                                   ` Andrea Arcangeli
2008-01-31  2:08                                 ` Christoph Lameter
2008-01-31  2:42                                   ` Andrea Arcangeli
2008-01-31  2:51                                     ` Christoph Lameter
2008-01-31 13:39                                       ` Andrea Arcangeli
2008-01-30 19:35                   ` Christoph Lameter
2008-01-28 20:28 ` [patch 3/6] mmu_notifier: invalidate_page callbacks for subsystems with rmap Christoph Lameter
2008-01-29 16:28   ` Robin Holt
2008-01-28 20:28 ` [patch 4/6] MMU notifier: invalidate_page callbacks using Linux rmaps Christoph Lameter
2008-01-29 14:03   ` Andrea Arcangeli
2008-01-29 14:24     ` Andrea Arcangeli
2008-01-29 19:51       ` Christoph Lameter
2008-01-28 20:28 ` [patch 5/6] mmu_notifier: Callbacks for xip_filemap.c Christoph Lameter
2008-01-28 20:28 ` [patch 6/6] mmu_notifier: Add invalidate_all() Christoph Lameter
2008-01-29 16:31   ` Robin Holt
2008-01-29 20:02     ` Christoph Lameter

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